Income Taxes (Reconciliation Of Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits, beginning of year	$ 1,181	$ 986	$ 737
Additions based on tax positions related to the current year	47	71	43
Additions for tax positions of prior years	24	197	325
Reductions for tax positions of prior years	(20)	(16)	(22)
Acquisitions, divestitures and other	(30)	7	9
Lapse of statute of limitations	(13)	(51)	(53)
Settlements	(38)	(12)	(42)
Effect of foreign currency translation	24	(1)	(11)
Unrecognized tax benefits, end of year	$ 1,175	$ 1,181	$ 986